Asset Impairment Expense (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2017	Jun. 30, 2016
Asset Impairment Expense [Line Items]
Impairment of Long-Lived Assets Held-for-use	$ 90		$ 235		$ 258	$ 394
Parent Company [Member]
Asset Impairment Expense [Line Items]
Impairment of Long-Lived Assets Held-for-use				$ 49
Kazakhstan Hydro [Member]
Asset Impairment Expense [Line Items]
Impairment of Long-Lived Assets Held-for-use	90		0		90	0
Kazakhstan [Member]
Asset Impairment Expense [Line Items]
Impairment of Long-Lived Assets Held-for-use	0	$ 94	0			0
buffalo gap II [Member] [Member]
Asset Impairment Expense [Line Items]
Impairment of Long-Lived Assets Held-for-use	0		0	159	0
DPL Subsidiary [Member]
Asset Impairment Expense [Line Items]
Impairment of Long-Lived Assets Held-for-use	0	66	235			235
Energy Storage [Member]
Asset Impairment Expense [Line Items]
Impairment of Long-Lived Assets Held-for-use	$ 0		0		$ 8	0
Long Lived Assets Held And Used [Member] | Stuart Station [Member]
Asset Impairment Expense [Line Items]
Assets, fair value		3
Long Lived Assets Held And Used [Member] | Killen Station [Member]
Asset Impairment Expense [Line Items]
Assets, fair value		$ 8	84			84
Long Lived Assets Held And Used [Member] | DPL Peaking Generation [Domain]
Asset Impairment Expense [Line Items]
Assets, fair value			$ 5			$ 5
Long Lived Assets Held And Used [Member] | buffalo gap II [Member] [Member]
Asset Impairment Expense [Line Items]
Assets, fair value				$ 92